The idea here is that the settings specified in the .sql file will override the settings in the .sql-connection file. The most common case (for which I wrote this) would be that they are not actually overlapping, like:

maindb.sql-connection
type: mysql
user: username
password: xxxyyy
host: 127.0.0.1
port: 3309
dbname: stats

pageviews.sql
connection: maindb
query: select * from pageviews where timestamp > "2012-01-01"

...but since we are using combine, it is also possible to override stuff you might need for some specific databases, even when it is specified in the sql-connection file. For example:

users.sql
connection: maindb
dbname:social
query: select * from users

salaries.sql
connection: maindb
dbname:economy
user:finance
password:secret
query: select * from salaries

Of course it would be possible to make the composition not allow overrides, or only allow it for certain fields, but I this approach seemed more flexible to me.